The present invention relates to a new method and system for operating a sensor.
Sensors, especially rate-of-rotation, or yaw rate, sensors, can be expediently installed in a housing together with an associated evaluating electronic unit. For this purpose, the sensors can be mounted together with other electronics on the same printed circuit board, or can be provided on a separate printed-circuit board. Yaw rate sensors are used, for example, in vehicle systems for electronic stability control (ESC), adaptive cruise control (ACC) and roll stability control (RSC). A yaw rate sensor detects rotation around the vertical axis of the vehicle. For this purpose, an oscillating element such as a tuning fork or oscillating body of some other construction is disposed inside the sensor. The oscillating element is excited to vibration and measures a deflection caused by coriolis force during rotation around a vertical axis. Known yaw rate sensors are described in WO 03/067190 A1, DE 102 15 853 A1, and DE 44 44 973 C2 and are usually manufactured as micromechanical components making them sensitive to shaking and other mechanical vibrations, which can cause false readings and even destruction of the sensors.
False readings are particularly critical with respect to the vehicle system applications noted above because false control signals (which do not correspond to true vehicle behavior) can be generated and endanger the vehicle and its occupants. Furthermore, the control system is not always capable of distinguishing false readings from the actual rate of rotation.
DE 100 22 968 A1 describes a cushioning and damping design for a printed-circuit board on which the sensor is mounted. This design, however, is not ideal because the electronics are considerably more expensive. Furthermore, it is technologically difficult to maintain control over such damping devices because cushioning and damping effects can vary over time.
Test results indicate that vibrations of a certain frequency range, particularly between 300 and 450 Hz, are responsible for impaired output signals of rate-of-rotation sensors. At and above a certain level of vibration, these vibrations may lead to DC offset drift of the output signal.
High-quality yaw rate sensors that are insensitive to vibrations and impacts can be used. However, because of the high price of such sensors, their use as mass-produced components in motor vehicles is impractical.